Peritoneal metastasis in colon cancer is staged as
High-Yield Explanation
T1 Invades submucosaT2Invades muscularis propriaT3Invades through the muscularis propria into perirectal tissuesT4aInvades through the visceral peritoneumT4bDirectly invades to adjacent organs or structuresN1aOne node positiveN1b2-3 nodes positiveN1cNo regional lymph nodes positive, but there are tumour deposits in the subserosa, Mesentery or non-peritonealized pericolic/ perirectal/ mesorectal tissues N2a4-6 lymph nodes positiveN2b7 or more lymph nodes positiveM1aMetastasis to one site or organ, without peritoneal metastasisM1bMetastasis to 2 or more sites or organs without peritoneal metastasisM1c Metastasis tothe peritoneal surface (alone or along with other site/organ)Ref: AJCC 8e